British musician Sir Elton John has said in an interview that he believes Jesus Christ would approve of gay marriages, and shared his admiration for the work Pope Francis has done so far, calling him "wonderful."

John's comments come days after the Vatican released a major new document speaking out against unjust discrimination against gay people but affirming traditional teachings on marriage, a viewpoint that Francis has supported.

"These are old and stupid things. If Jesus Christ was alive today, I cannot see him, as the Christian person that he was and the great person that he was, saying this could not happen," John told Sky News on Sunday, speaking out against Church of England rules banning gay clergy from getting married.

"He was all about love and compassion and forgiveness and trying to bring people together and that's what the church should be about."

John, who is planning on marrying his partner David Furnish next year in what he says will be a low-key wedding, added that Pope Francis is a "wonderful" man who has done a lot to push for tolerance and humility.

"The new Pope has been wonderful, he's excited me so much," the musician said.

"He's stripped it (the Church) down to the bare bones and said it's all basically about love."

But last week's Instrumentum Laboris, a report resulting from the pope's call in October 2013 for Roman Catholic bishops around the world to convene and discuss matters of family and the Christian faith, said that the Church finds same-sex marriages to be incompatible with the faith.

"On unions of persons of the same sex, the responses of the bishops' conferences refer to Church teaching. 'There are absolutely no grounds for considering homosexual unions to be in any way similar or even remotely analogous to God's plan for marriage and family. [...] Nonetheless, according to the teaching of the Church, men and women with homosexual tendencies 'must be accepted with respect, compassion and sensitivity. Every sign of unjust discrimination in their regard should be avoided,'" the lengthy document reads.

It added that every bishops' conference has spoken out against redefining marriage between a man and a woman.

Pope Francis said in a September 2013 interview about homosexuality: "The teaching of the church, for that matter, is clear and I am a son of the church, but it is not necessary to talk about these issues all the time."

He added that the Catholic Church's catechism condemns homosexual acts, but called on the Church to love gays and lesbians, who "must be accepted with respect, compassion and sensitivity."

John has long been campaigning for gay rights issues, and back in January spoke out against Russia's controversial law that seek to protect children from gay "propaganda" ahead of the 2014 Winter Olympic Games that were held in Sochi.

"Whatever the intention of Russia's homosexuality and pedophilia propaganda laws, I am absolutely clear from my own personal experience that it is proving deeply dangerous to the LGBT community and deeply divisive to Russian society," John wrote in a blog post, and added that he would like the opportunity to speak with President Vladimir Putin the next time he visits Russia.

"I will see Putin and talk to him - I don't know what good it will do though," the musician told Sky News about a planned meeting in November with Putin, who has shared of his admiration for the singer and said that millions of Russians loved John "despite his orientation."

Last July, John again praised Francis after the pope was named "Man of the Year" by the Italian edition of pop-culture magazine Vanity Fair.

"Francis is a miracle of humility in the era of vanity," John wrote for the magazine. He added that he hopes that the pope will be able to bring his message "to the most marginalized in society, to those communities which, at this time of their lives, they desperately need your love."